実験的膀胱腫瘍に対するビタミンEの抗腫瘍効果に関する研究

Abstract

3週齢のWistar系雄ラットを4群に分け, 30週齢までビタミンE欠乏食, コントロール食, ビタミンE 40 mg/100 g食, ビタミンE 60 mg/100 g食, にて飼育し, その間9週齢より17週齢まで8週間, 各群に0.05% BBN含有水を投与し, 30週齢時に屠殺して, 膀胱腫瘍の発生状態, 心採血による血清ビタミンE濃度, 血中リンパ球数, 血中CD4/CD8および組織のリンパ球浸潤度を測定し, ビタミンEの抗腫瘍効果を検討した.1)肉眼的にはビタミンEの抗腫瘍効果はなかった.2)組織学的にはビタミンE欠乏群とビタミンE 60 mg群に有意差がみられ, ビタミンEの抗腫瘍効果は認められたが, なお, コントロール群との間に有意差はなかった.3)血中リンパ球数には各群間で差はなかったが, 病理組織検査におけるリンパ球浸潤度はビタミンE投与群が高値を示し, また, CD4/CD8は血中ビタミンE濃度が上昇するにつれ高値となり, 一方, 腫瘍異型度は低下し, ビタミンEは濃度依存性に腫瘍細胞の抗原性増強に関与することにより抗腫瘍的に作用することが示唆された

The anticancer activity of vitamin E may involve its functions as an antioxidant free radical scavenger, and immunomodulater. We studied the effect of vitamin E on rats with bladder tumors induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN). Three-week-old male Wistar rats were given a diet containing 0 (A), 2 mg (B:control), 40 mg (C), and 60 mg (D) of vitamin E per 100 g of food, respectively, until they were 30 weeks old. The carcinogen, 0.05% BBN was given in drinking water to the rats for 8 weeks from the 9th week of age, and all rats were killed at 30 weeks old. The number and the size of the tumors, the thickness of epithelial cell layers in hyperplasia, the diameter of papillary tumor, and the cellular atypia were assessed by using a point method according to U-test. As assessment of immune response, the lymphocyte count in blood, the degree of lymphocyte infiltration in tissue, and CD4 (helper/inducer-T cell)/CD8 (suppressor/cytotoxic-T cell) ratio in blood by flow cytometry using monoclonal antibodies were evaluated according to the t-test. Moreover, the correlation between CD4/CD8, cellular atypia, and serum level of vitamin E were evaluated by coefficient of correlation. There were no differences between any two groups in the number or the size of the tumors. The cellularity in group A was significantly higher than that in group D (p less than 0.05). The point of the cellular atypia tended to decrease, with increasing dose of vitamin E, but not significantly, whereas the CD4/CD8 tended to increase by increasing the dose of vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)